Passive transfer of transplantation immunity was accomplished in inbred guinea pigs with tritiated thymidine-labeled lymphoid cells sensitized to homologous tissues. Autoradiographs of the homologous skin graft sites disclosed the presence of relatively few or no labeled cells at the site of rejection.
Passive transfer of transplantation immunity was also accomplished with sensitized lymphoid cells enclosed in cell-impenetrable Millipore chambers. Previous studies with passive transfer of tuberculin sensitivity in guinea pigs revealed that the specifically sensitized cells could be easily found at the site of challenge in the presence of specific antigen and were ineffective when enclosed in Millipore chambers. It appeared, then, that the homograft reaction and delayed sensitivity of tuberculin type were achieved by different immunologic mechanisms within the same species.